Tumor necrosis factor‐α regulates human follicular dendritic cell‐secreted protein gene transcription in gingival epithelial cells.

Follicular dendritic cell‐secreted protein (FDC‐SP) is a secreted protein expressed in follicular dendritic cells, periodontal ligament and junctional epithelium. To elucidate the transcriptional regulation of the human <italic>FDC‐SP</italic> gene by tumor necrosis factor‐α (TNF‐α), we conducted real‐time PCR, Western blotting, transient transfection analyses with chimeric constructs of the <italic>FDC‐SP</italic> gene promoter linked to a luciferase reporter gene, gel mobility shift and chromatin immunoprecipitation assays using Ca9‐22 gingival epithelial cells. TNF‐α (10 ng/ml) induced <italic>FDC‐SP</italic> mRNA and protein levels at 3 hr and reached maximum at 12 hr. In transient transfection assays, TNF‐α (12 hr) increased the LUC activities of constructs between −116<italic>FDCSP</italic> and −948<italic>FDCSP</italic> including the human <italic>FDC‐SP</italic> gene promoter. Transcriptional stimulations by TNF‐α were partially inhibited in the −345<italic>FDCSP</italic> constructs that included 3‐bp mutations in the <italic>YY1</italic>,<italic> GATA</italic>,<italic> CCAAT enhancer‐binding protein 2</italic> (<italic>C/EBP2</italic>) and <italic>C/EBP3</italic>. Transcriptional activities induced by TNF‐α were inhibited by tyrosine kinase, MEK1/2 and phosphoinositide 3‐kinase inhibitors. The results of ChIP assays showed that YY1, GATA and C/EBPβ transcription factors interacted with the <italic>YY1</italic>,<italic> GATA</italic>,<italic> C/EBP2</italic> and <italic>C/EBP3</italic> elements that were increased by TNF‐α. These studies show that TNF‐α stimulates human <italic>FDC‐SP</italic> gene transcription by targeting <italic>YY1</italic>,<italic> GATA</italic>,<italic> C/EBP2</italic> and <italic>C/EBP3</italic> in the <italic>FDC‐SP</italic> gene promoter. [ABSTRACT FROM AUTHOR]